However, these days the prominent North-West Tasmanian is just as happy to be championing same-sex marriage as he is woodchopping.

The reason? His daughter Sally, her partner Lily and their daughter Wren, who soon turns one.

Foster will speak on Tuesday in support of same-sex marriage at a forum in Hobart - something he admits would not have happened before Sally sat down with him and his wife Jan four years ago.

"I think she (Sally) didn't want to (come out) earlier, because I was a bit anti-that and maybe she didn't want to upset me," he said.

"She sat my wife and I down and said `I want to tell you something' and that's how we spoke as a family."

The 54-year-old Latrobe resident said his close relationship with Sally had not changed as a result of that conversation, but his views had.

"Everyone has an opinion, but once it's close to home you realise what's important. My daughter is the same daughter I reared and just because her sexual preferences are different from mine doesn't mean a thing," he said.

"She is a nurse, she has a beautiful partner and a child and if they wish to get married, I can't see why they can't."

Foster said his wife's recent health scare had the family reassessing what was important - and counting its blessings.

While some of his mates "that you could call bushies" accepted Sally's news with little fuss, Foster said he had copped flak from others.

He also knew of a woodchopper who, upon learning his daughter was a lesbian, cut off all communication with her and her child.

The Greens already support same-sex marriage and, last month, the Tasmanian ALP voted in favour of law reform.

Tasmanian Labor Senator Carol Brown will be among those backing the same change at the party's national conference.

Her online survey on the issue closes today.

"I believe that there is majority support within our community for same-sex couples to have the right to marry," Senator Brown said.

"A change in the ALP national platform will ensure that we can return to the Parliament in 2012 and fight to fulfil our equality agenda with a change to the Marriage Act."

Tasmanian Gay and Lesbian Rights Group spokesman Rodney Croome said Mr Foster's story illustrated how Tasmanian attitudes have evolved.

"I'm confident that with supporters like David Foster this reform is inevitable," he said.

Foster hoped that by speaking up he would encourage other parents to be out and proud about their children -no matter what their sexual preference.

"I have a high profile, but that doesn't mean I'll sit on the fence and be quiet just because I might offend somebody," he said.

"Sally is my daughter, and I love her and I'm proud of her. Sometimes you've got to stand up and be heard."